Posted
by
samzenpuson Friday November 30, 2012 @05:01AM
from the it's-in-the-blood dept.

sciencehabit writes "People usually find out that they have cancer after developing symptoms or through a screening test such as a mammogram—signs that may appear only after the cancer has grown or spread so much that it can't be cured. But what if you could find out from a simple, highly accurate blood test that you had an incipient tumor? By sequencing the abnormal DNA that a tumor releases into a person's bloodstream, researchers are now one step closer to a universal cancer test. Although the technique is now only sensitive enough to detect advanced cancers, that may be a matter of money: As sequencing costs decrease, the developers of the method say the test could eventually pick up early tumors as well."

Hold the phone, there, Alfred. You have to think about how early you want to be able to find mutating cells. There is a sweet spot of detection - when the cancer is not yet so advanced that it can be treated - below which you may want to think twice about going. If this research results in the ability to detect cells as soon as they mutate, you and the media may think this is a great advance, but the body's immune system is able to sense and kill the vast majority of mutating cells before they grow into a tumor. At a certain detection level, the test is going to give positive results for "cancer" for most people. Then what do you do? You go to the doctor and the doctor tells you that you have malignant cells in your body. Are you going to not worry or are you going to demand treatment?

Even better, the false positive rate is important. Regular testing for ovarian cancer in women is something you simply should not do; an ovarian cancer test should only be done if your doctor thinks you have ovarian cancer. Because of the rate of false positives, the rate of false positives in follow-up tests, the rate of complications, and the rate of death in complications, it turns out that roughly 1 in 1000 women who don't get regular testing would die of ovarian cancer, whereas if every woman over age 50 got regular ovarian cancer testing once a year we'd see a death rate of 3 in 1000 due to complications from unnecessary surgery to treat the non-existent cancer in false-positive cases.

If this leads to people looking for cancer that doesn't exist or isn't important, a lot of false positives will start occurring. Even if it's highly accurate at detecting cancer, it won't tell you anything about the cancer. Now you have to look for it. So many cancer tests, so much false positive... you might find several cancers that don't actually exist, because the tests raise false positives occasionally and you're running tests for everything. False positives lead to unnecessary treatment, which is expensive and harmful. You're better off playing cancer roulette.

So the logical question is... just how much money is required to change this sentence "This is an exploding field." He thinks such tests could reach the clinic within 5 to 10 years. " to read ".... within 1 to 2 years"?

Actually tests like this(not sure if its the same one or not) was something that really excited Steve Jobs towards the end(and something that supposedly his son was researching). He seems to have thought that sequencing is the next big tech boom, and paid a lot of money to have his own cancer sequenced.... So there was at least one billionaire interested in it.

And that's the key. There are billionaires, and they have families, and they can and want to be able to have this. I see no reason to not give billionaires first place in the extremely expensive treatment world and make and design things for the to spend a fortune on.
The funding will benefit others. Its maths - If you have 5 billion and treatment costs 1 billion you still have.... erm.. no don't tell me.. 5-1= erm.. Oh yeah, A fuck ton of cash left over. I've no idea why Apple isn't a player the cancer

The methodology seems to account for the many types of cancer, at least in theory, since it's based on finding differences in DNA sequences. As long as a fingerprint exists wouldn't this technique find it?

But this also sounds very preliminary. The sample size was very small and it took a month to get the results.

I'm not sure that scanning for genetic changes will turn out to be useful.

Not every genetic change results in cancer as many will result in the cells dying off or being innocuous. Working on bringing the detection threshold down to low enough values to detect small tumours may just end up detecting many small cancers.

In addition, recent work shows that many small cancers are not as problematic as as long been thought. We now know that the body naturally wipes out many cancers without help. Detecting the small cancers that need treatment is much harder than it appears.

Exactly. ISTR reading that at any one time, most people have dozens of small 'cancers' but in most cases, the body destroys them before they get a hold. It's only when our own defences fail that the cancer goes on to become a 'proper' one and become a health hazard.

I really think you guys are worried about the wrong end of this. It is highly unlikely that this test is going to be too sensitive any time soon...quite the opposite, the key will be making it sensitive enough to be useful. One or a few cells aren't going to make enough DNA that you would have any reasonable chance of picking it up in a random blood sample. There would have to be some critical mass there already, and who knows, but I would guess that the amount of DNA released into the blood by even an in situ is going to be too small to detect.

It is true that cells mutate fairly frequently, but most of these are not "cancer". Cancer implies that it grows invasively. These sequencing tests would be looking for certain genes known to be linked with cancer. Perhaps over time they will develop heuristics that will allow for detection of mutations not previously characterized but initially it would probably be limited to cancer genes already understood. But my initial concern is whether early cancers dump enough genetic material into the blood for this to be useful for early detection. I'll bet that it is only after it becomes invasive that it releases enough DNA to detect.

You appear to have missed my point. It is now known to be normal for people to have cancer cells. These small cancers are normally caught by the immune system & eliminated so trying to treat every cancer has been shown to be counter-productive (chemo is poison that just kills the cancer faster than it kills you, radiation has side-effects & surgery has it's own issues). The old objective from decades ago of finding the cancer while it is small & easily treated has disappeared. What we now know t

[I missed this and it is now old, but I'll respond anyway.] Actually, I completely got your point and tried to explain that you are confusing a mutation with cancer. Two points.1. A single/few cell mutation that is destroyed is not cancer. By definition, cancer is an uncontrolled, invasive growth. If it is controlled right away, it isn't cancer.2. I am saying that the technique would not detect these single cell mutations because the amount of DNA they would release into the blood would be minimal and t

Ah, I see where you misunderstood me. The small cancers that I talked about originally are much more than just single cell mutations. The study I read said that when Breast cancer detection got down to around 1mm that many of the growths were spontaneously being suppressed in the control groups. Statistical verification through biopsies in other groups proved that many of these small growths were indeed cancers. The fact that in many cases the growths disappear without treatment shows that the hosts immune

The problem with scanning for genetic change is some of us are variatic in nature. Human genetic physiology is interesting...human cellular proteins include receptors that allow for stress signals to encode useful genetic changes. In response to environmental pressure, humans are actually capable of rewriting their own DNA to adapt. Pretty much any animal immune system--including the human immune system itself--functions similarly, but internally: T4 cells sample a pathogen and then modify their own DN

Just throw enough data at an algorithm and it'll learn. There are only so many ways a DNA mutation can lead to unrestrained growth - even if there thousands of such mutations, eventually you should be able to pick up most of them. If you can detect 99% of all cancer patients, you have an essentially perfect solution.

Likely the only thing that is going to prevent cancer is the death of the organism. With enough basic research it might be possible to find a single or at least a small number, of molecular mechanisms that trigger abnormal cell growth. Then again, it might not. Even if you find them, it doesn't mean you can interrupt or modify them on an organismal level.

So doctors do what they CAN do. And cancer treatments are certainly better than before - less toxic, more effective. But we don't know enough cell an

I hope they develop better ways of locating the cancer in the body as well, otherwise it will be just like it is now. Dear Sir/Madam your tumor marker has shot up 10x, but we can't find where it's spread, so sorry.

Most interesting cancer treatment research to me:
- Dichloroacetic acid (it's as close to free as possible and has known side effects and is available some places now) but seems to work best in combination with chemo
- anti-CD47 (has the potential to treat numerous cancers, but it's early)

Your headline is more true than you realize... although you don't realize it.

Something like 2/3rds of the population that we would consider to die of "old age" (generally defined as dying of a condition that predominately kills the elderly, and doing so at around, or greater, than the average lifespan for a developed country), have been discovered, upon death, to have cancer of some sort, but cancer that did NOT contribute to their death. IIRC, the most "popular" are Prostate, Breast, and Brain tumors. Some of those tumors may have been decades old, but slow-growing and non-aggressive enough to simply not be an issue.

Not all cancer is worth detecting if it's almost inevitable that you'll die from simply "wearing out" first.

Some screening tests for cancer byproducts already exist, like the PSA test for prostate cancer. Other early-detection tests abound, such as Mammograms and Colonoscopies. While some of the screening tests, such as the Pap Smear, have shown to dramatically reduce cancer deaths, others, such as the PSA and Mammogram have detected a lot of cancers, but done absolutely bupkis to reduce death rates when given to populations not otherwise at high risk. Colonoscopies work, but are extremely expensive vs. the benefit they provide. (As in, it'd be a lot more efficient to spend healthcare dollars elsewhere, and there are other screening tests nearly as effective that are much cheaper.) Apparently they don't do a good job detecting aggressive cancers in those populations early enough to make a difference. With how fast some aggressive cancers work, the tests might have to be administered several times a year (at the cost of countless billions) to make any difference.

In addition, the PSA and Mammogram HAVE caused billions to be spent on procedures with quite severe side effects to further diagnose, and treat, problems that almost certainly would not have killed their "victims." Most Prostate tumors grow slowly enough that you could leave it alone for the rest of your life, and die of something else instead; meanwhile, prostate cancer treatment almost always causes problems with incontinence and impotence; two major quality of life issues. Most "breast cancers" detected by mammograms are Ductal Carcinoma In Situ, another type of cancer that is unlikely to kill you any time soon.

We need to think VERY carefully before rolling out any MORE widespread cancer screening tests, since many of the ones we have now simply don't work.

Medical screening is a tricky subject - see the wikipedia article [wikipedia.org] for a better overview of it all. However tests aren't 100% foolproof, and if you look up terms such as sensitivity, specificity, positive predictive value, false positive etc. on wikipedia it will give you a general indication of how these tests really work.
I do not believe that you can have a test that screens for all cancer that is useful. Or if I put it this way when will it pick up cancer? Can it pick up ALL cancers early enough that

A good screening test is cheap, minimally invasive, and very, very sensitive. It does not matter if you get false positives, because you will never act on just the result of a screening test alone. You want a test that absolutely does not, however, give you false negatives. That way you reduce the whole population to the sick, and the falso positives. This new population is then re-screened with highly specific, expensive diagnostic tests that determine if the person does or does not have the disease in que

The cancer rate is increasing because of three major trends: improved diagnostics. improved treatments and longer life spans in general (you have to die of something). As numerous posters have pointed out, uncontrolled cell division - AKA cancer - is a common occurrence in the human body. So, roughly 100% of people would screen positive for cancer if we had a sensitive enough test and we tested enough people enough times.

We are also getting better at treating many, but certainly not all cancers. So y

Yerba mate, green tea, and black tea are all highly anti-cancer. Mate is actually awesome for this; steamed green tea is pretty close; black tea less so, but it has its own strengths over the others. It's worth having a pot of Earl Grey or Irish Breakfast Tea in the morning, and a pot of green tea (gunpowder, any of the various $15-$200 Sencha greens, etc) in the afternoon.

Meanwhile people cry about HFCS, which is an abomination but relatively harmless; look at all the wheat we eat, and our response is to eat whole grains because they're less bad. People figure this out and go Atkins, instead of just eating less than 3000 calories from wheat every day. Over-salted, fumigated crap gets pureed, strained, cooked, then mixed with benzoates and sorbates and parabeens for us to eat or rub onto our skin. All that's bad, but removing it all won't really help if you keep eating crap--like tons of wheat, tons of rice, tons of greasy fatty shit, all things that are good for you but not so god damn much with so little else--and keep sitting on your ass all the time.

Those toxic chemicals will go away if you bike to work every day. Live 5 miles from work? That's 10 miles a day. Suck down potassium and magnesium and sodium out of a CamelBak, chomping on Clif bars if you need it, and shove a greasy full English down your throat in the morning cooked in a ton of lard. Hell, use the canned sorbated bullshit, your body will just shove it out your lymph system while you burn through all that crap.

Meanwhile people cry about HFCS, which is an abomination but relatively harmless

No, it isn't. The high consumption of HFCS and ordinary table sugar are likely a primary component of the high rise in rates of diabetes and obesity, along with associated diseases of the heart and clogged arteries: Is Sugar Toxic? [nytimes.com]

Those toxic chemicals will go away if you bike to work every day.

Uh huh. Or if you drink a lot of water, you'll piss them all out. Please stop with the homegrown health science.

If you consume, say, Botulinum, or a small amount of heavy metal (lead, mercury), and you're highly active, some of that will leave your system--if the dose is low enough to not kill you immediately. If you consume HFCS and you're highly active, you'll burn it off as energy. It's relatively harmless. Parabens and sorbates and all the other preservatives and extenders and weird salts and crap aren't that harmful, and they're metabolized away more quickly when your metabolism is higher.

If you consume HFCS and you're highly active, you'll burn it off as energy.

It has to be metabolized first, and it's the by-products of metabolism that are the problem.

Fat-soluble toxins get moved into the blood stream when consolidated fats are mobilized for energy, a cycle that occurs under extended periods of elevated metabolism (i.e. you start burning fat--you might burn and store at relative equillibrium, but you WILL burn some of your stored fat if you're on a bicycle for an hour).

Even if this is true, which I'd need to see the specific metabolic mechanism to verify, the idea that you can just eat a bunch of crap and burn it off with biking an hour to work a day is a dangerous and simplistic idea. You can't see inside your arteries to know that you are doing enough: "During the Korean War, pathologists doing autopsies on American soldiers killed in battle noticed that many had significant plaq

It has to be metabolized first, and it's the by-products of metabolism that are the problem.

While fructose absorption and modification by the intestines and liver does differ from glucose initially, the majority of the fructose molecules are converted to glucose or metabolized into byproducts identical to those produced by glucose metabolism. Consumption of moderate amounts of fructose has also been linked to positive outcomes, including reducing appetite if consumed before a meal, lower blood sugar increases compared to glucose, and (again compared to glucose) delaying exhaustion if consumed during exercise.

Fructose from HFCS is supplied intentionally in Gatorade; from Dextrose in powdered Gatorade. It's done that way because Fructose is important for this particular use--consumption of Fructose improves performance during strenuous physical activity. The byproducts of Fructose metabolism are, unsurprisingly, carbon dioxide and water. This is because Fructose is metabolized by enzymatic conversion into Glycogen, which involves weakening the molecule--it's susceptible to similar molecular forces as Glucose,

there's always a small amount that is easily tolerated and is removed eventually, and speeding up that process simply means you can handle that much more.

Even if true, your advice was patently dangerous: "Those toxic chemicals will go away if you bike to work every day."

Don't eat like crap and expect a daily bike ride to take care of all associated problems. Exercise, skip all the added sugar, and eat wholesome food. That's the best bet if you are concerned about living long and healthy.

Even if true, your advice was patently dangerous: "Those toxic chemicals will go away if you bike to work every day."

Don't eat like crap and expect a daily bike ride to take care of all associated problems. Exercise, skip all the added sugar, and eat wholesome food. That's the best bet if you are concerned about living long and healthy.

The impact of a moderate but reasonable amount of physical activity is bigger than the impact of cutting 40 ounces per day of Dr. Pepper out of your diet. The impact of high-intensity exercise--jogging, bicycling, whatnot--for half an hour a day will completely eliminate the impacts of 40 ounces per day of Dr. Pepper. Food in general contains generally recognized as safe levels of anything it does contain, including preservatives that by nature are toxic to cellular activity--those toxins a

The impact of a moderate but reasonable amount of physical activity is bigger than the impact of cutting 40 ounces per day of Dr. Pepper out of your diet. The impact of high-intensity exercise--jogging, bicycling, whatnot--for half an hour a day will completely eliminate the impacts of 40 ounces per day of Dr. Pepper.

That's a quantitative statement without any references as to how you come to your conclusion. Yes, I get it, exercise is beneficial. Now how much?

Food in general contains generally recognized as safe levels of anything it does contain, including preservatives that by nature are toxic to cellular activity--those toxins are diluted when consumed, after all.

GRAS is a weak standard. Even salt is GRAS, and it is linked to high blood pressure. The FDA is not going to regulate a common food like sugar even if over-consumption leads to diabetes and cardiovascular disease.

The bottom line is that you are ignoring demonstrated dangers with diet and latching on to exercise as the main thing to worry about. Exercise is importa

You can't eat a bunch of extra sugar, especially at the amounts Americans do, without consequences.

1) I can and have.

2) You can't lead a highly sedentary lifestyle without consequence. No diet will make you healthy. Contrastingly, you can be healthy with a fairly imperfect diet if you're active. Evolutionarily, we didn't have perfect diets harmonized in a medical clean room to evolve from; we ate whatever crap we could get, high amounts of fruit sugar, tons of meat, whatever, and we were healthy. Problem is we had to climb trees (Persimmon trees are 35ft tall! Apple trees aren't little shrubs!

And you know this how? How old are you, and how long have you been eating a bunch of extra sugar, and how much? I got away with eating terribly and little exercise all through my 20s. It eventually caught up with me. You can't see inside your arteries, or check your liver for fatty deposits, or know how well your pancreas is doing, or any number of things that might be going wrong. You just assume that because you feel fine now you aren't doing long-term damage.

Funny, I don't think there were any soda trees around in prehistoric times. The modern diet of low-fiber, refined food with added sugar is nothing like the diets that we evolved on. Having fruit as part of a varied diet is not the same thing as chugging down multiple sodas a day.

Everything was low-fat, low-sugar, with no massive starch sources like pertaters?

Everything was low-fat, low-sugar, with no massive starch sources like pertaters?

I haven't said a word about fat, or even starch for that matter. I'm talking about all the added sugars, refined foods, and lack of fiber and nutrients that you find in a modern, Western diet. Humans evolved as hunter-gatherers, and soda didn't grow on trees. Trying to favorably compare the modern crap diet to the diets that humans were evolved to eat is absurd.

Potatoes are effectively identical to refined sugar and white wheat grain. You actually have to refine them to make them healthy--you need to cook, then freeze, then reheat them to raise the resistant starch levels above 4% (you can get 23%-35% easy enough, 23% being the realistic number and 35% being reachable but not by intent). RS is essentially identical to non-soluble dietary fiber in its function. All other mass in the potato that's not in the skin is white, refined sugar; don't tell me it's differ

Potatoes provide no nutrients except in the skin. Fructose is harmless in the presence of glucose--sucrose is metabolized essentially identical to glucose, and the HFCS in soda is 55/45 rather than the 85/15 mostly-fructose stuff. Uptake of fructose is reduced outside the presence of glucose, and then the liver process it differently without glucose (and inefficiently).

Potatoes provide no nutrients except in the skin. [..] Essentially, potatoes are worse than soda. Hostess Cupcakes provide more nutrition than mashed potato.

You keep on spouting uninformed bullshit. It's tiresome, and I'm going to have to stop responding to you if you keep it up. You can't expect to be taken seriously when you get basic shit wrong that can easily be looked up while trying to act like an expert.

Your reference for potatoes shows a pretty high number for "dietary fiber"--resistant starch is effectively dietary fiber, but it's present between 4% and 23% in potatoes, and the 23% number is reachable by boiling and then freezing and then re-heating--and then vitamin C (in damn near everything), a little protein, and a small amount of iron and calcium.

And here I assumed Hostess cupcakes were made out of wheat... they're about on par, with more fat, less carbs, and half the calories, about equal nutrit

Your reference for potatoes shows a pretty high number for "dietary fiber"--resistant starch is effectively dietary fiber, but it's present between 4% and 23% in potatoes, and the 23% number is reachable by boiling and then freezing and then re-heating--and then vitamin C (in damn near everything), a little protein, and a small amount of iron and calcium.

All that and you skipped the potassium, something potatoes are well-known for, plus the B6, as well as a host of other vitamins and minerals that aren't listed in the other two foods mentioned. And that's only without the skin; keep in mind we started talking about the potato as an offshoot of foods we evolved on. My guess is that they ate their potatoes baked, with the skin. And as hunter-gatherers and not farmers, they ate a variety of foods, not just potatoes, and almost certainly not boiled, mashed pota

Just one more quick note: another category of healthy foods people eat are nuts, which are high in good fat, have fiber, vitamins and minerals, and protein. The idea that the modern diet chock full of added sugars was anything remotely what we evolved to eat is absurd.

Potassium and other vitamins are in potato skin. You cited boiled potato without skin--and the link you gave didn't list potassium or B6. Most people eat baked potato out of the skin and throw the skin away, or they eat mashed potatoes.